Allograft tissue forms are useful in orthopaedic and neurosurgery. In practice, processed human tissue is delivered to the hospital and eventually to the surgeon in a form useful for surgical implantation. There are presently available a number of kinds of packaging for sterile specimens. One form of commonly used packaging is to provide the allograft tissue in a freeze-dried state, in a glass bottle with a stopper or other waterproof container. This type of packaging provides the advantage of stabilizing the tissue for storage in a warehouse or hospital supply room at normal room temperature conditions. Freeze-dried packaging works effectively for relatively small sizes of allograft tissues. Various types of tissue such as demineralized bone powders, chips, and small machined shapes such as pins, screws and spinal spacers are effectively packaged in this form. Currently there are no known effective tissue storage systems available for general use.
Large tissue forms cannot be effectively freeze-dried because their thickness and cross section is too great to allow for complete removal of moisture in the freeze-dry process. Such tissue forms include full form long bones e.g., femora, tibiae, humerii, fibulae and ilea and large cross sectional cuts of same. These large tissue forms require low temperature freezing in order to provide shelf life stability.
This frozen format is a serious problem for manufacturers of forms of allograft bone, and presents problems for the hospital and surgeon user, as effective storage to achieve tissue stability requires temperatures as low as −80° C. These low temperatures create problems for viewing, inventorying, and controlling the shipment of the individual packages of tissue forms. Specifically, the tissue form, when inspected or handled for shipping or selected for use, must be clearly seen by the user to select the right size, shape and condition of the bone for the specific surgery. Hence, this viewing requires some transparent element of the packaging to allow for visualization of the tissue. The deep frozen state and low temperatures required for tissue stability creates heavy moisture condensing on the packaging from the environmental air, which obscures the visualization of the tissue form. Current packaging uses transparent plastic bags with appropriate labeling and identification information to resolve this problem and provide suitable visibility. The use of plastic packaging in and of itself has problems because it is not convenient to store the irregularly shaped bone and consequently irregular shaped packaging that occurs from the plastic bags currently in use. This irregularity of the packaging shape makes for difficulty in storing the allograft tissue forms in low temperature freezers which are commercially available. The difficulty is manifested by requiring staff to sort through many bags in a freezer to find a specific individual tissue form of the right shape and size for the surgical use indicated causing potential problems as to the package sterility, integrity and recorded location. The condensation problem again comes into play where the contents, once removed from the freezer, will quickly condense over and make it difficult to read the labeling because of the low temperature condition and condensation that ensues from that system. Further, modern medical packaging includes bar code labeling to allow for automation of inventory control as well as maintaining a shipment and location trail for specific tissue forms. The tissue form package bar codes are also easily obscured by the condensation and frost that develops on packaging when the same are constantly shuffled causing exposure from the low temperature state to atmospheric conditions. As previously noted, condensation develops and unused packages put back into the freezer cause opaque frost to form over the labeling, which obscures the bar code and prevents it from being easily read by the automated machinery.
Accordingly, a packaging system has been developed to handle the various frozen form of allograft tissue which resolves these problems.